G0300101 Proposal of Acquisition Way of Inelastic Strain Range Using Lead-Free Solder Lap Joint Type Shear Specimen

Abstract

Solder joints under temperature changes are destroyed by low cycle fatigue. So, it is important that evaluations of thermal fatigue life of the lead-free solder joints are performed. Evaluations of thermal fatigue life of the solder joints are done by next process. First, low cycle fatigue properties of the solder are got by conducting mechanical fatigue examinations. Second, equivalent inelastic strain range is got by conducting the FE structural analysis of the solder joints. At last, the fatigue life of lead-free solder joints is got from the properties and the equivalent inelastic strain range. Therefore, when we estimate the fatigue life of solder joints, we have to get accurate low cycle fatigue properties of the solder. There, the size effects, the interface influences and direction of stress on solder joints have to be considered. Therefore, in this study, an acquisition way of inelastic strain range by lead-free solder lap joint type shear specimen was proposed. Next, we conducted a tension-compressive test using Sn3.5Ag0.5Cu0.07Ni0.01Ge lead-free solder lap joint type shear specimen and got equivalent inelastic strain range for the low cycle fatigue properties actually.